1. Field of the Invention
This invention relates to tools for removing key operated lock cylinders, and specifically for removing lock cylinders which are located in the steering columns of automobiles and similar vehicles.
2. Description of the Prior Art
U.S. Pat. No. 3,972,103, issued Aug. 3, 1976, to David L. Kenyon discloses an automobile lock removal tool operative to remove a lock cylinder from within its housing by exerting a pulling force about the outer flange of the cylinder. Such force is communicated to the cylinder by means of a collet which grips the outer shoulder of the lock cylinder. An outer shell fits over the collet and abuts against the lock housing on the steering column of the automobile. The collet is drawn into the shell by turning a bolt which is inserted through the rear of the shell and threaded into the collet. The force thus applied to the cylinder acts to break the outer surface of the cylinder behind a retaining pin so that the cylinder can be easily removed from the housing.
The tool disclosed in U.S. Pat. No. 3,972,103 is suitable only for use in conjunction with lock cylinders mounted on steering wheel columns of General Motors automobiles manufactured from around 1968 to 1976. This is so because the collet disclosed in the patent requires that a predetermined minimal clearance exist between the outside edge of the cylinder plug flange and the portion of the housing which extends outwardly thereabout. In the 1977 model year of General Motors automobiles, this clearance has been substantially reduced in that the overall diameter of the outside cylinder flange has been increased. This alteration prevents the use of the Kenyon or similar tool which may be easily worked in and behind the plug flange to apply an outward force sufficient to break the entire cylinder out from the housing. Thus, in order to remove the lock assembly from the newer line of General Motors automobiles, it becomes necessary to remove the steering wheel and disassemble the steering column in order to free the cylinder retaining pin. As explained in the Kenyon patent, such an operation involves a complicated procedure and leads to considerable expenditures in time and money.